This application generally relates to footwear products, and in particular, to structures and fabrication of rubber-based footwear.
Footwear may be constructed with a wide range of natural and synthetic materials. Selection of one or more materials for a footwear may be based on various considerations and purposes, including utility, durability, comfort, and ease of manufacturing. One of the frequently-used materials for footwear products is rubber materials. A rubber may be either a natural rubber material or a synthetic rubber material. The shoe sole of a footwear, for example, may be constructed by using one or more rubber parts or components. U.S. Pat. No. 5,743,027 issued on Apr. 28, 1998 to Barma describes an example of a rubber shoe sole formed from directly engaging adjacent rubber sole layers to each other by vulcanization at an elevated temperature. This technique allows the final shoe sole to have an integrated rubber structure.